JP6075128B2 - Drive circuit device - Google Patents

Description

  The present invention relates to a drive circuit device.

  In general, the driving power is supplied to the electric motor by using a driving circuit (inverter) in which switching arms, each of which includes switching elements such as FETs connected in series, are connected in parallel. Conventionally, as a drive circuit device (motor control device) having such a drive circuit, by using a circuit board having a multilayer structure in which an insulating layer is interposed between a plurality of circuit conductor layers on which circuit patterns are formed, A device that is downsized is known (for example, Patent Document 1).

  By the way, since a large drive current for driving the electric motor flows in the drive circuit, there is a problem in that the amount of heat generation is large and overheating tends to occur. Therefore, in the drive circuit device disclosed in Patent Document 1, a switching element is mounted on one side surface of the circuit board, and a heat sink or other radiator is connected to the other side surface so as to be able to transfer heat, thereby driving circuit (switching element). ) Is efficiently radiated to prevent overheating of the drive circuit.

JP 2009-277726 A

  In recent years, there has been a demand for further miniaturization of drive circuit devices. However, in the configuration in which the switching element is mounted on one side surface of the circuit board as in the above-mentioned Patent Document 1, there is a limit to downsizing because of the necessity of securing a mounting area on the circuit board. Therefore, the development of a new technology that can further reduce the size of the drive circuit device has been demanded.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a small drive circuit device.

A drive circuit device that solves the above problems includes a circuit board on which a drive circuit is formed by connecting a plurality of switching arms having first and second switching elements connected in series in parallel, and heat of the circuit board. And a circuit board having a multilayer structure in which an insulating layer is interposed between a plurality of circuit conductor layers including a circuit pattern made of a conductive material. be those with, the first and second switching elements, said first switching element and the second switching element and said circuit conductor layers the rewritable interposed between, the first switching element in the stacking direction Provided on the circuit board such that a range where the second switching element is located overlaps a range where the second switching element is located, and the first switching element and the second switching element The circuit pattern of the interposed a circuit conductor layers between, Rutotomoni drawn in a direction perpendicular to the stacking direction from the circuit board, the lead unit thermally transferable connected is formed in the radiator, the The gist is that the radiator is formed with an extending portion extending from the portion protruding in the direction orthogonal to the stacking direction from the edge of the circuit board along the stacking direction to the lead-out portion side. .

  According to the above configuration, since the range where the first switching element and the range where the second switching element are located overlap in the stacking direction, the first and second switching elements are mounted on one side surface of the circuit board. In comparison, the circuit board can be reduced in size.

Here, in the said structure, the site | part pinched from the lamination direction both sides by the 1st switching element and the 2nd switching element arises in a circuit board. And since both the heat which generate | occur | produced in the 1st switching element and the heat which generate | occur | produced in the 2nd switching element are transmitted to the said site | part, a heat | fever will become easy to trap. In this regard, in the above configuration, the circuit pattern of the interposed a circuit conductor layer between the first switching element and second switching element, is drawn out of the circuit board Rutotomoni, heat transfer coupled to the radiator A drawn portion is formed. Moreover, in the said structure, the extension part extended in the drawer | drawing-out part side along the lamination direction from the site | part which protruded in the direction orthogonal to the lamination direction rather than the edge part of a circuit board is formed in the heat radiator. Therefore, the heat of the part sandwiched from both sides in the stacking direction by the first switching element and the second switching element can be transmitted to the extension part of the radiator through the extraction part of the circuit pattern to efficiently dissipate heat. it can. Thereby, a circuit board can be reduced in size, realizing high heat dissipation performance.

In the driving circuit device, each of the first and second switching elements is embedded in the circuit board, and the radiator is connected to the circuit board so as to transfer heat so as to sandwich the circuit board from both sides in the stacking direction. Tei Rukoto is preferable.

  According to the said structure, it can thermally radiate | emit efficiently to the lamination direction both sides of a circuit board via a heat radiator, and higher heat dissipation performance is realizable.

  According to the present invention, the circuit board can be reduced in size.

The block diagram which shows the outline of a drive circuit device. The fragmentary sectional view of the drive circuit device of one embodiment. The fragmentary sectional view of the drive circuit device of another example. The fragmentary sectional view of the drive circuit device of another example.

Hereinafter, an embodiment of a drive circuit device will be described with reference to the drawings.
A drive circuit device 1 shown in FIG. 1 supplies drive power to an electric motor 2 used as a drive source of an electric power steering device that applies assist force to a steering system. As shown in FIG. 1, the drive circuit device 1 includes a drive circuit 3 that supplies drive power to the electric motor 2 and a control circuit (microcomputer) 4 that controls the operation of the drive circuit 3. That is, the drive circuit device 1 of the present embodiment is configured as a motor control device (ECU). The electric motor 2 of the present embodiment employs a three-phase (U phase, V phase, W phase) brushless motor.

  The drive circuit 3 includes upper stage FETs (Field Effect Transistors) 12Hu, 12Hv, and 12Hw as first switching elements connected to the in-vehicle power source (battery) 11, and lower stage FETs 12Lu as second switching elements connected to the ground. 12Lv, 12Lw. Then, the driving circuit 3 includes a switching arm 13u in which the upper FET 12Hu and the lower FET 12Lu are connected in series, a switching arm 13v in which the upper FET 12Hv and the lower FET 12Lv are connected in series, and a switching in which the upper FET 12Hw and the lower FET 12Lw are connected in series. It is formed by connecting the arms 13w in parallel. That is, the drive circuit 3 is configured as a well-known PWM inverter formed by connecting three switching arms 13u, 13v, 13w corresponding to the motor coils 2u, 2v, 2w of each phase of the electric motor 2 in parallel.

  Specifically, the drain electrodes de of the upper stage FETs 12Hu, 12Hv, and 12Hw are connected to the in-vehicle power source 11 via power source (drain) wirings 15u, 15v, and 15w, respectively. The source electrodes se of the lower stage FETs 12Lu, 12Lv, and 12Lw are connected to the ground via grounding (source) wirings 16u, 16v, and 16w, respectively. The source electrodes se of the upper stage FETs 12Hu, 12Hv, and 12Hw and the drain electrodes de of the lower stage FETs 12Lu, 12Lv, and 12Lw are connected to each other via series wirings 17u, 17v, and 17w. The series wirings 17u, 17v, and 17w are connected to the motor coils 2u, 2v, and 2w of the respective phases via power lines 18u, 18v, and 18w, respectively. In addition, the upper stage FETs 12Hu, 12Hv, and 12Hw and the lower stage FETs 12Lu, 12Lv, and 12Lw have parasitic diodes D that allow energization from the source electrode se side to the drain electrode de side.

  The control circuit 4 is connected to the gate electrodes ge of the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw via signal (gate) wirings 19u, 19v, 19w, respectively. Then, by outputting a motor control signal to each gate electrode ge, on / off of the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw is controlled. That is, the motor control signal is a gate on / off signal that defines the switching states of the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw. The control circuit 4 according to the present embodiment receives the steering torque, the vehicle speed, and the rotation angle of the electric motor 2, and the control circuit 4 outputs motor control signals based on these state quantities. Thus, the operation of the electric motor 2 is controlled.

  In the drive circuit device 1 configured as described above, the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw are turned on / off in response to the motor control signal, and the energization patterns to the motor coils 2u, 2v, 2w of the respective phases. Is switched, the power supply voltage of the in-vehicle power supply 11 is converted into three-phase drive power and output to the electric motor 2.

  Next, the configuration of the circuit board 21 on which the drive circuit 3 is formed will be described. Since the cross-sectional structure around the switching arms 13u, 13v, 13w in the drive circuit device 1 is common, the configuration of the U-phase switching arm 13u will be described for convenience of description, and the V-phase and W-phase switching arms 13v will be described. , 13w will be omitted.

  As shown in FIG. 2, the circuit board 21 is a multi-layered board in which an insulating layer is interposed between a plurality of circuit conductor layers. The circuit board 21 is accommodated in the case 24 of the drive circuit device 1 in a state where heat sinks 22 and 23 as heat radiators are connected to the side surfaces on both sides in the stacking direction (vertical direction in FIG. 2) so as to be able to transfer heat. Has been.

  More specifically, the case 24 is formed in a square box shape. The heat sinks 22 and 23 are formed in a flat plate shape and are fixed to the inner surface of the case 24. The case 24 and the heat sinks 22 and 23 are each made of a material having high thermal conductivity such as an aluminum alloy.

  The circuit board 21 includes first to fourth circuit conductor layers 31a to 31d and first to third insulating layers 32a to 32c interposed therebetween. In the present embodiment, the first circuit conductor layer 31a, the first insulating layer 32a, the second circuit conductor layer 31b, the second insulating layer 32b, and the third circuit conductor layer are sequentially arranged from the heat sink 22 side (the lower side in FIG. 2). 31c, the third insulating layer 32c, and the fourth circuit conductor layer 31d are laminated. A sheet-like insulating material 25 is interposed between the first circuit conductor layer 31 a and the heat sink 22 and between the fourth circuit conductor layer 31 d and the heat sink 23. In addition, the insulating material 25 of this embodiment is comprised with the insulating material with high heat conductivity, such as a ceramic.

  The first to fourth circuit conductor layers 31a to 31d are first to fourth circuit patterns 33a to 33d having a predetermined shape formed by removing a part of a conductor foil made of a conductive material such as a copper foil, respectively. The gap between the wirings constituting the first to fourth circuit patterns 33a to 33d is filled with an insulating resin material. The first circuit pattern 33a includes the power supply wiring 15u, the second circuit pattern 33b includes the serial wiring 17u and the signal wiring 19u, and the third circuit pattern 33c includes the ground wiring 16u and the signal wiring 19u. It is included.

  The first to third insulating layers 32a to 32c are made of an insulating resin material, and maintain insulation between the first to fourth circuit patterns 33a to 33d. In addition, via holes (interlayer connection holes) 34 are formed in the circuit board 21 and extend through the predetermined circuit conductor layers and insulating layers in the stacking direction. An interlayer connection member 35 made of a conductor material such as copper is inserted into the inner periphery of the via hole 34, and circuit patterns of different layers are electrically connected to each other via the interlayer connection member 35. .

  The upper stage FET 12Hu is embedded in the first insulating layer 32a in a bare chip state, and the lower stage FET 12Lu is embedded in the second insulating layer 32b in a bare chip state. That is, the second circuit conductor layer 31b is interposed between the upper stage FET 12Hu and the lower stage FET 12Lu. Further, the upper stage FET 12Hu and the lower stage FET 12Lu are arranged so that the range in which the upper stage FET 12Hu is located and the range in which the lower stage FET 12Lu is located overlap in the stacking direction.

  The drain electrode de of the upper stage FET 12Hu is electrically connected to the power supply wiring 15u of the first circuit pattern 33a, the source electrode se is electrically connected to the series wiring 17u of the second circuit pattern 33b, and the gate electrode ge. Are electrically connected to the signal wiring 19u of the second circuit pattern 33b. Further, the drain electrode de of the lower stage FET 12Lu is electrically connected to the series wiring 17u of the second circuit pattern 33b, the source electrode se is electrically connected to the ground wiring 16u of the third circuit pattern 33c, and the gate electrode ge. Are electrically connected to the signal wiring 19u of the third circuit pattern 33c. Thus, a switching arm 13u is formed in which the upper stage FET 12Hu and the lower stage FET 12Lu are connected in series.

  Here, in the present embodiment, as described above, the second circuit conductor layer 31b is sandwiched between the upper stage FET 12Hu and the lower stage FET 12Lu from both sides in the stacking direction. Therefore, since both the heat generated in the upper FET 12Hu and the heat generated in the lower FET 12Lu are transmitted to the portion sandwiched between the upper FET 12Hu and the lower FET 12Lu of the second circuit conductor layer 31b, the heat is easily trapped. End up.

  In consideration of this point, the second circuit pattern 33b is continuous with the series wiring 17u, and extends in an orthogonal direction (left and right direction in FIG. 2) orthogonal to the stacking direction, and is drawn out to the outside of the circuit board 21. 41 is formed. The heat sinks 22 and 23 are formed with extending portions 22a and 23a extending from the portion protruding in the orthogonal direction to the edge of the circuit board 21 to the drawing portion 41 side in the stacking direction. And the drawer | drawing-out part 41 is connected to both extension part 22a, 23a via the sheet-like insulating material 42 so that heat transfer is possible.

  The circuit board 21 is manufactured by first removing a part of the conductive foil provided on both sides of the insulating layer to be one of the first to third insulating layers 32a to 32c by etching or the like. One of four circuit patterns is formed. Subsequently, the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw are appropriately connected to the circuit pattern, and a new conductive foil is laminated by sandwiching an insulating resin material serving as an insulating layer between the circuit patterns. The process of forming a circuit pattern on the conductor foil is repeated. The circuit board 21 is manufactured by forming the via hole 34 and providing the interlayer connection member 35 on the inner periphery of the via hole 34.

Next, the operation of this embodiment will be described.
By supplying drive power to the electric motor 2, the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, 12Lw generate heat. At this time, the heat generated in the upper stage FETs 12Hu, 12Hv, and 12Hw is dissipated by being transmitted to the heat sink 22 through the first circuit conductor layer 31a, and through the lead-out portion 41 of the second circuit conductor layer 31b. Then, heat is dissipated by being transmitted to the extended portions 22a and 23a of the heat sinks 22 and 23. On the other hand, the heat generated in the lower FETs 12Lu, 12Lv, and 12Lw is transferred to the heat sink 23 through the third circuit conductor layer 31c, the third insulating layer 32c, the interlayer connection member 35, and the fourth circuit conductor layer 31d. The heat is dissipated and the heat is dissipated by being transmitted to the extending portions 22a and 23a of the heat sinks 22 and 23 through the lead portion 41 of the second circuit conductor layer 31b. Thereby, the heat of the whole circuit board 21 is efficiently radiated.

Next, the effect of this embodiment will be described.
(1) Since the range in which the upper stage FETs 12Hu, 12Hv, and 12Hw are positioned and the range in which the lower stage FETs 12Lu, 12Lv, and 12Lw are positioned overlap in the stacking direction, the area of the circuit board 21 can be reduced. Further, since the lead portion 41 is formed in the second circuit pattern 33b, and the lead portion 41 is connected to the extending portions 22a and 23a of the heat sinks 22 and 23 so as to be able to transfer heat, the upper FETs 12Hu, 12Hv, 12Hw and the lower FETs 12Lu, 12Lv, The heat of the part sandwiched from both sides in the stacking direction by 12 Lw can be efficiently radiated through the extraction portion 41. Thereby, the circuit board 21 can be reduced in size while realizing high heat dissipation performance.

  (2) The upper stage FETs 12Hu, 12Hv, and 12Hw and the lower stage FETs 12Lu, 12Lv, and 12Lw are embedded in the circuit board 21 in a bare chip state, and the heat sinks 22 and 23 are placed on the circuit board 21 from both sides in the stacking direction. It was connected so that heat could be transferred from both sides. Therefore, heat can be efficiently radiated to both sides in the stacking direction of the circuit board 21 via the heat sinks 22 and 23, higher heat dissipation performance can be realized, and the circuit board 21 can be further downsized.

In addition, the said embodiment can also be implemented in the following aspects which changed this suitably.
In the above embodiment, the heat sinks 22 and 23 are formed in a flat plate shape. However, the present invention is not limited to this. For example, fins or the like may be formed on the side surface of the heat sinks 22 and 23 opposite to the circuit board 21. Further, a flow path through which a coolant such as water or air passes may be formed inside the heat sinks 22 and 23. Further, the case 24 may function as a radiator by fixing the circuit board 21 to the inner surface of the case 24 without providing the heat sinks 22 and 23 separately.

  -In above-mentioned embodiment, although the drawer | drawing-out part 41 was connected so that heat transfer was possible to both extension part 22a, 23a, it connects not only to this but to any one of extension part 22a, 23a so that heat transfer is possible. May be.

  -In the said embodiment, the number of a circuit conductor layer and an insulating layer, the connection of each layer, etc. can be changed suitably. Specifically, a circuit conductor layer connected via an insulating layer and an interlayer connection member 35 (via hole 34) is added between the first circuit conductor layer 31a and the heat sink 22, or the lower FET 12Lu is connected. The three-circuit conductor layer 31c may be connected to the heat sink 23 via the insulating material 25 so as to be able to transfer heat. A plurality of circuit conductor layers may be interposed between the upper FET 12Hu and the lower FET 12Lu.

  In the above embodiment, the upper stage FETs 12Hu, 12Hv, 12Hw and the lower stage FETs 12Lu, 12Lv, 12Lw are embedded in the circuit board 21. May be provided. In the example shown in FIG. 3, the lower stage FET 12Lu is provided in a form exposed on the side surface of the circuit board 21, and the bus bar 51 serving as the ground wiring 16u is electrically connected to the source electrode se of the lower stage FET 12Lu and the gate electrode ge The bus bar 52 serving as the signal wiring 19u is electrically connected to the. In this case, it is preferable to connect the heat sink 23 to the bus bars 51 and 52 via the insulator 53 so that heat can be transferred, as shown in FIG.

  In the above embodiment, the drive circuit 3 is formed using the FET. However, the present invention is not limited thereto, and the drive circuit 3 may be formed using another switching element such as an IGBT (insulated gate bipolar transistor). . In the configuration using the IGBT, a diode is used in combination. Specifically, as shown in FIG. 4, the collector electrode coe of the upper IGBT 55Hu and the cathode electrode cae of the upper diode 56Hu are electrically connected to the power supply wiring 15u of the first circuit pattern 33a. The emitter electrode ee of the upper stage IGBT 55Hu, the anode electrode ae of the upper stage diode 56Hu, the collector electrode coe of the lower stage IGBT 55Lu, and the cathode electrode cae of the lower stage diode 56Lu are electrically connected to the series wiring 17u of the second circuit pattern 33b. The emitter electrode ee of the lower IGBT 55Lu and the anode electrode ae of the lower diode 56Lu are electrically connected to the ground wiring 16u of the third circuit pattern 33c. The gate electrode ge of the upper stage IGBT 55Hu is connected to the signal wiring 19u of the second circuit pattern 33b, and the gate electrode ge of the lower stage IGBT 55Lu is connected to the signal wiring 19u of the third circuit pattern 33c.

In the above embodiment, an FET or the like in which a bare chip is sealed (packaged) with a sealing material or the like may be used as the switching element.
In the above embodiment, the drive circuit device 1 includes the control circuit. However, the present invention is not limited thereto, and a control circuit device including the control circuit may be separately provided, and the drive circuit device 1 may not include the control circuit. .

  In the above embodiment, a brushless motor is used as the electric motor 2. However, the present invention is not limited to this, and for example, a DC motor with a brush may be used. In this case, the drive circuit 3 is configured as an H bridge circuit in which two switching arms are connected in parallel.

  -In above-mentioned embodiment, although drive electric power was supplied to the electric motor 2 for giving assist force using the drive circuit apparatus 1, it is not restricted to this, For example, it uses as a drive source of other apparatuses, such as an electric pump apparatus. Driving electric power may be supplied to the electric motor.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(A) The drive circuit device, wherein the switching element is embedded in the circuit board in a bare chip state. According to the above configuration, the circuit board can be further downsized.

  DESCRIPTION OF SYMBOLS 1 ... Drive circuit device, 3 ... Drive circuit, 12Hu, 12Hv, 12Hw ... Upper stage FET, 12Lu, 12Lv, 12Lw ... Lower stage FET, 13u, 13v, 13w ... Switching arm, 15u, 15v, 15w ... Power supply wiring, 16u, 16v , 16w ... ground wiring, 17u, 17v, 17w ... series wiring, 18u, 18v, 18w ... power line, 19u, 19v, 19w ... signal wiring, 21 ... circuit board, 22, 23 ... heat sink, 22a, 23a ... extension 31a to 31d: first to fourth circuit conductor layers, 32a to 32c ... first to third insulating layers, 33a to 33d ... first to fourth circuit patterns, 41 ... extraction part, 55Hu ... upper IGBT, 55Lu ... Lower IGBT, 56Hu ... Upper diode, 56Lu ... Lower diode.

Claims (2)

A circuit board configured with a drive circuit formed by connecting a plurality of switching arms having first and second switching elements connected in series in parallel, and a radiator for radiating heat of the circuit board to the outside The circuit board is a drive circuit device using a multilayer substrate in which an insulating layer is interposed between a plurality of circuit conductor layers including a circuit pattern made of a conductive material,
Said first and second switching elements, said first switching element and the second The rewritable the circuit conductor layer is interposed between the switching element, a range and said that the position of the first switching element in the stacking direction 2 provided on the circuit board so as to overlap the range where the switching element is located,
Wherein the circuit pattern of the interposed a circuit conductor layer between the first switching element and the second switching element is drawn in a direction perpendicular to the stacking direction from said circuit board Rutotomoni, can heat transmitted to the radiator The drawer part connected to is formed ,
The radiator is formed with an extending portion extending from the portion protruding in the direction orthogonal to the stacking direction from the edge portion of the circuit board to the lead-out portion side along the stacking direction. Drive circuit device. The drive circuit device according to claim 1,
The first and second switching elements are each embedded in the circuit board,
The radiator is a driving circuit apparatus characterized by being thermally transferred connected to the circuit board so as to sandwich the circuit board from both sides in the laminating direction.